support SIMD

[ZhenNan2016]

Hi, all.
Excuse me, do the current release versions of clickhouse support SIMD by default? That is, the support of vectorization parallel execution engine.
Or do I still need to compile the source code myself to support SIMD?

[UnamedRus]

By default released binaries support vectorization & SIMD to some reasonable degree.
IE, at least older versions of ClickHouse, didn't enabled AVX512 globally, as it will explode generated binary size.
#34071 (comment)
But, in specific places, support for AVX512 was added via dynamic dispatch, just short list of them:
https://github.com/ClickHouse/ClickHouse/pulls?page=2&q=avx512

[ZhenNan2016]

By default released binaries support vectorization & SIMD to some reasonable degree. IE, at least older versions of ClickHouse, didn't enabled AVX512 globally, as it will explode generated binary size. #34071 (comment) But, in specific places, support for AVX512 was added via dynamic dispatch, just short list of them: https://github.com/ClickHouse/ClickHouse/pulls?page=2&q=avx512

Hi, @UnamedRus
Thank you for your reply.
Excuse me, My current version of the clickhouse is 22.8.4.7. The server's CPU also supports SSE4.2 and AVX512 command sets.
What method should be used to confirm that SIMD has been used for speed up reading and writing?
I executed the following statement:
SELECT name, value, changed FROM system.settings WHERE name LIKE '%vector%' OR name LIKE '%simd%';
The returned allow_simdjson field has a value of 1.
Executed:
SELECT query, ProfileEvents['VectorizedRowsFiltered'] AS vectorized_rows FROM system.query_log WHERE type = 'QueryFinish' ORDER BY event_time DESC LIMIT 1
The returned “query” field is an insert sql statement, while the “VectorizedRowsFiltered” field is 0.
Is there any other way to confirm whether SIMD is used?
Thanks a lot.

[UnamedRus]

My current version of the clickhouse is 22.8.4.7. The server's CPU also supports SSE4.2 and AVX512 command sets.

Expect that all SIMD (SSE4.2, AVX2) up to AVX512 (not included) is used.
Consider upgrading to more recent release, to be able to use AVX512

VectorizedRowsFiltered
There is no such event

You can check compilation flags from here:

SELECT *
FROM system.build_options
WHERE name = 'CXX_FLAGS'

[ZhenNan2016]

My current version of the clickhouse is 22.8.4.7. The server's CPU also supports SSE4.2 and AVX512 command sets.

Expect that all SIMD (SSE4.2, AVX2) up to AVX512 (not included) is used. Consider upgrading to more recent release, to be able to use AVX512

VectorizedRowsFiltered
There is no such event

You can check compilation flags from here:

SELECT *
FROM system.build_options
WHERE name = 'CXX_FLAGS'

​Hi, @UnamedRus
From the query results:
It includes -mssse3, -msse4.1, and -msse4.2.

I asked about the background of this matter because I deployed a standalone version of Clickhouse and encountered issues with slow data loading and lagging. So I want to improve the concurrency performance of queries.
The version of Clickhouse that I am currently using is 22.8.4.7, and the services in the current production environment are standalone, that is, non clustered. The resources of this machine:
vCPU: 96
total used free shared buff/cache available
Mem: 369 53 32 0 283 318
Swap: 0 0 0
​
Currently, it stores over 300T of data.
Now, during peak periods, there are hundreds of requests that experience lag and slow data loading; Sometimes with dozens of requests, this situation can also occur. Our business uses SQL to query data, which involves some complex queries such as joining multiple tables.
The current situation is that some requests take up a lot of memory, causing insufficient memory and preventing other requests from being processed. There are also requests that report errors or exit due to insufficient memory.
Is there any good parameter tuning solution for this standalone architecture?

At present, we hope to meet the following basic requirements:

1. Not lagging.
2. No abnormalities occurred.
   Thank you a lot.